Hello and thanks for any help... I have a 1970 Chevelle with factory AC . I replaced the blower motor but other than HI it just doesnt seem to move much air.
Has anyone used a late model Fan Blower motor that moves alot of air ? If so , what was the blower unit from ?
Or any other mod's to make the system work better ?

I replace the motor on a Chevy PU years ago, and got it from the junk yard, and was not from the same type vehicle. So I put the motor in with the fan. It ran good but little air came out. Took it back out, and checked it with the old one.The fan blades were in opposite direction, just changed the fan,and worked like it should.Maybe that's your problem?

Hello and thanks for any help... I have a 1970 Chevelle with factory AC . I replaced the blower motor but other than HI it just doesnt seem to move much air.
Has anyone used a late model Fan Blower motor that moves alot of air ? If so , what was the blower unit from ?
Or any other mod's to make the system work better ?

Although those systems were kind of wimpy when new, the problem isn't likely the fan motor. The most likely cause is the outside of the evaporator caked with 38 years of dust, dirt, and debris from the unfiltered air. Pull the blower motor and have a look.

I have had the entire unit out and restored. New Evap., POA , restored box , wiring , Fan motor , relays , etc...
Seems to work - Ok on HI , but the other speeds move little air.
Has anyone done anything to update the motor or squirrel cage for more Air ?
Someone told me to take one from a late model car , like a Monte Carlo, but the blower motor is shaped different. Just looking for some good idea's from someone who has already been down this road....

I am pretty sure its the AC Blower as it has a ground and power terminals. Like i said, it works ok on HI , just the other three speeds dont move enough air or very little.
Is there a better cage , faster blower motor , better relay ?
Does anyone know what other blower might fit the case ?

IF it's workig on high, and barely on any of the other speed selects, it's a current problem. Check the blower motor resistor that is screwed into the heater box on the engine side. It's the one with the 3 spring looking coils.

Many of the doors to direct the air are vacuum operated. The engine needs to be running for the controls to work properly and get the air into the cab. If you have tried it with the engine running, are the controls working ??

IF it's workig on high, and barely on any of the other speed selects, it's a current problem. Check the blower motor resistor that is screwed into the heater box on the engine side. It's the one with the 3 spring looking coils.

I have the same issue. However, I first had a problem with no high on the fan. I was then advised (on here) that there is seperate fuses for the other speeds, and one high speed fuse that I located under the hood. Is it possible that that High speed fuse is good and the other bad?

Same kind of question here. I've taken everything out and cleaned up the whole A/C system, new blower motor, etc. I know the car has a 40 year old design, but is there a more powerful blower motor that might make it match today's late model standards. My friends new Civic A/C feels so nice, are new cars systems just better at sealing in cool air?

Same kind of question here. I've taken everything out and cleaned up the whole A/C system, new blower motor, etc. I know the car has a 40 year old design, but is there a more powerful blower motor that might make it match today's late model standards. My friends new Civic A/C feels so nice, are new cars systems just better at sealing in cool air?

Newer cars are just better designed for better airflow and volume.
Back in circa 1970, most GM cars were known to be rather wimpy as far as airflow out of the ducts, except on High Blower (Thus the High Blower Relay to put as much power as possible to the motor). Then they were only "kinda" wimpy. Chrysler products were even worse at that time. Ford was the only one back then that could boast that the output from the dash vents could "blow your hair back". Even they weren't up to todays expectations.
The High line GM cars (big Buicks, Olds, Etc) were better than the Low or Intermediate Line cars for airflow, but even they were not what you would expect today from even a "cheap" car.

Cars of the 40's and 50's had very poorly designed airflow (heater) systems that were just barely better than nothing. The systems of the 60's and 70s were comparatively far superior performers as the years progressed, but surely not even good compared to today. Fast forward to the 80's and they were better yet, but still not up to todays standards. Only in the late 80s and into the 90s did GM produce MVAC systems that compare to today's systems. That same progression held true with the other manufacturers, but GM historically has always had the "wimpyist" airflow systems as compared to the "other guys". Actually, that still seems to hold true even today IMHO. The difference just isn't as noticeable.

There might be ways to improve the airflow of those older cars, but I've never delved into it.

Today, the best you can do is meticulously seal leaks in the ductwork, make sure everything is nice and clean, and make sure the blower motor and it's wiring is up to par on these older cars. They were great performers compared to their predecessors, but you will never get 2009 performance out of them.

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